Obtaining arthroscopic access into orthopedic joints to perform surgical procedures can be extremely challenging. This is particularly true of the hip joint, which has two tissue barriers that must be crossed in order to gain access to the inner part of the joint. The outer barrier is known as the capsule, a series of tight overlapping ligaments surrounding the joint. The area within the capsule is known as the peripheral compartment.
Within the peripheral compartment, the joint is fluidly sealed by a skirt-like tissue known as the labrum which is attached to the acetabular rim and hugs tightly around the base of the femoral head. The labrum/femoral head interface creates a vacuum seal within the joint which helps to hold the femoral head tightly within the acetabulum. In order to gain access to the central compartment (i.e., the portion of the joint within the labrum lying between the femoral head and acetabulum), the seal of the labrum must be broken and instruments then introduced into the very narrow opening between the bottom edge of the labrum and femoral head.
In arthroscopic surgery, access to the peripheral compartment is typically obtained through the use of elongated tubular devices (e.g., arthroscopic portals or cannulas) which are inserted through the patient's skin and through the ligaments of the capsule so as to provide a tunnel or lumen through which instruments may be introduced. Two to three such portals are typically employed, one being used for placement of an arthroscope and the remaining portal(s) being available for the introduction of other instruments.
In order to gain access to the central compartment, surgeons typically use a distraction table, a surgical table that includes a post placed against the patient's perineum and a tensioning device which fastens to the patient's foot or ankle and allows high forces to be exerted on the patient's leg to distract the femur and create space within the joint. However, these tables are not only large, cumbersome and expensive, but they limit the mobility of the joint during the procedure and frequently produce complications such as nerve damage.
Methods and devices have been proposed for distracting the hip joint without using a distraction table. For example, commonly assigned U.S. patent application Ser. No. 12/483,446, filed Jun. 12, 2009, entitled “Methods and Apparatus for Joint Distraction”, the entirety of which is incorporated by reference herein, and U.S. patent application Ser. No. 12/726,268, filed Mar. 17, 2010, the entirety of which is incorporated by reference herein, disclose various internal distraction devices for distracting the hip and other joints. These devices use balloons or other expandable features placed within the central compartment to displace the femoral head further away from the acetabulum in order to allow access for surgical instruments. While such devices eliminate the need for a distraction table, challenges may still be encountered when introducing these devices into the peripheral and central compartments. Further, even where a conventional distraction table is used, the placement of portals and the introduction of instruments into the peripheral and central compartments remain challenging.